Facile NiCo2S4/C nanocomposite: an efficient material for water oxidation

Abstract

The water oxidation in alkaline media is a kinetically sluggish process and it requires an active electrocatalyst for overall water splitting which is a challenging task to date. Herein, we formulate a platform for the design of efficient NiCo2S4/C nanocomposite using earth abundant and nonprecious materials. The nanocomposites are prepared by scale up hydrothermal method using different carbon contents from acid dehydrated sucrose. They are structurally and morphologically characterized by various analytic techniques. The scanning electron microscopy has shown few microns flower-like morphology of nanocomposite and hexagonal crystalline phase is identified by X-ray diffraction (XRD). Further, high-resolution transmission electron microscopy supported the XRD results, and C, Ni, Co and O elements were found in the composition nanocomposite as investigated by energy-dispersive spectroscopy. The most active nanocomposite reaches a current density of 20 mA·cm−2 at potential of 285 mV vs reversible hydrogen electrode. The nanocomposite is kinetically supported by 61 mV·dec−1 as small Tafel slope. The nanocomposite is stable and durable for 40 h. The electrochemical impedance spectroscopy described a small charge transfer resistance of 188.4 Ω. These findings suggest that the NiCo2S4/C nanocomposite could be used as a promising material for an extended range of applications particularly in energy technology.